A gas turbine is a type of internal combustion engine that has a rotating compressor coupled to a downstream turbine, with a combustion chamber located between the compressor and the turbine. Gas turbines are sometimes referred to as combustion turbines. Fuel is mixed with air in the combustor, and the mixture of fuel and air is ignited. Combustion products are forced into the turbine, where gas flow is directed over turbine blades to spin the turbine and power the compressor. In some instances the gas turbine can be used to drive a mechanical output.